HLA-DRB1 and hydrops fetalis: Out of all the detected haplotypes, two revealed frequencies close to 3%: HLA-A*01:01:01/HLA-B*08:01:01/HLA-C*07:01:01/HLA-DRB1*03:01:01, HF 3.33%, identified in 27 individuals, and HLA-A*02:01:01/HLA-B*18:01:01/HLA-C*17:01:01/HLA-DRB1*11:04:01 (2.84%, 23 individuals) (Table 2).